Due to the wide lens there's quite some lens distortion in your footage. The 3d space in matchmover or your 3d app has no such distortion. You have to find out the distortion of your lens by taking pictures of a distortion grid with it. Matchmover has settings for distortion.
A possible workflow for this is to first undistort the footage in a compositing software or matchmover itself, matchmove it, compose the cg on it and then redistort it for final output.
And I might add setting the focal length to a known value is useless, unless you take into account the crop factor and provide the correct chipsize.